My cats never fight, just some wrestling and Hanna has an annoying habit of picking on Abby and Bo - running after them and mock-attacking them.

But the dogs...argh. It has gotten better since they are all older now, but we had major problems before. We have two dogs who think they are dominant (Bandit and Gandy), and even Rocky will get picked on sometimes. So far they haven't hurt each other too severely, but twice one of them had to go get stitches, and once I had to visit the ER because I got in the middle and got bit on the leg. And Abby the cat for some reason thinks she needs to referee the dogs, so whenever there is a fight she comes running. She got bit bad once, it abcessed and she almost died. So now when there is a fight, I know better than to get in the middle of it, I grab Abby and put her somewhere she won't get hurt.